Ship outside plates, underwater structures, fishnets and the like are used in water, particularly in seawater over a long period of time, and therefore if many undersea lives such as hydrozoans, Bugula neritina, sea lettuces, green lavers, serpulas, oysters and the like are stuck and grow proliferously on parts brought into contact with seawater, original functions of ships, underwater structures, fishnets and the like are likely to be damaged.
In order to solve such problems as described above, antifouling paints are applied widely on the surfaces of ship outside plates, underwater structures, fishnets, instruments making use of seawater and the like for the purpose of preventing undersea lives from being stuck.
Antifouling paints comprising an organopolysiloxane as a principal component do not contain an antifouling agent such as cuprous oxide and the like and are nontoxic, and therefore they have been widely known.
For example, JP-B 2522854 (patent document 1) discloses curable organopolysiloxane compositions comprising a primary component that comprises (A) an organopolysiloxane in which both ends of a molecular chain are blocked by a silanol group or a hydrolyzable group, (B) an organosilane represented by a formula R1aSiX4-a, wherein R1 represents a non-substituted or substituted monovalent hydrocarbon group having 1 to 8 carbon atoms, X represents a hydrolyzable group and a represents 0 or 1, or a partial hydrolysate thereof and (C) an organopolysiloxane having at least one group represented by a formula ≡SiR2OSiR3bY3-b in a molecule, wherein R2 represents a non-substituted or substituted divalent hydrocarbon group or a divalent hydrocarbon group having an ether bond, R3 represents a non-substituted or substituted monovalent hydrocarbon group, Y represents a hydrolyzable group and b is 0, 1 or 2, provided that when R2 is the divalent hydrocarbon group having an ether bond, excluded is an organopolysiloxane in which two or more trimethylsiloxy groups are bonded to a Si atom directly linked to a carbon atom of the above hydrocarbon group, and cured products of the composition.
JP-B 63-2995 (patent document 2) discloses nontoxic antifouling paint compositions obtained by mixing a chemical reaction curable silicone rubber, petrolactam or a petrolactam/liquid paraffin mixture and a silicone oil having a low viscosity. JP-A 01-252677 (patent document 3) discloses underwater antifouling coating agents comprising a reaction curable silicone rubber and a specific copolymer as essential components. JP-A 03-255169 (patent document 4) discloses nontoxic antifouling paint compositions comprising a reaction curable silicone resin composition and a silicone resin having an alkoxy group at a molecular end. JP-B 2509674 (patent document 5) discloses nontoxic antifouling paint compositions comprising (a) a reaction curable silicone rubber, (b) a water repellent organic compound and (c) a hydrolyzable silyl group-containing acryl copolymer obtained by reacting a silane compound having a an acetoxy group or a ketoxym group as a hydrolyzable group with a copolymer [I] of (i) a (meth)acrylic alkyl ester with (ii) at least one monomer selected from (meth)acrylic acid and a (meth)acrylic lower hydroxyalkyl ester.
JP-A 2001-139816 (patent document 6) discloses curable compositions comprising an organopolysiloxane having a condensation-reactive functional group at both ends of a molecule and a hydrophobic silica. JP-A 2001-181509 (patent document 7) discloses curable compositions comprising an organopolysiloxane having a condensation-reactive functional group at both ends of a molecule, a hydrophobic silica and a hydrophilic silica.
However, an antifouling property of antifouling coating films obtained from the above antifouling paints is exerted depending to a large extent on components such as silicone oil and like which are released with the passage of time, and therefore when releasing these components finishes, the antifouling property has been lowered to make it difficult to exert the antifouling property over a long period of time.
Patent document 1: JP-B 2522854
Patent document 2: JP-B 63-2995
Patent document 3: JP-A 01-251677
Patent document 4: JP-A 03-255169
Patent document 5: JP-B 2509674
Patent document 6: JP-A 2001-139816
Patent document 7: JP-A 2001-181509